The engine is longitudinal isn't it? Why can't they push the wheels further forward?

Yes, it is; And the problem is teh same as with Audi, as the engine in a longitudinal/FWD car needs to sit infront of the axle (unlike traverse, where it can sit on top basically), as the drive shats connect to the differential behind the gear box, which is behind the engine; so all that goes in front.

Subaru though is in theroy slightly better of (however, not making visual use of it), as it is an opposed horizontal "Boxer", so just 2 cylinders per bank long, unlike say an Audi 4 cylinder or V8, that is double the length in the numbers of cylinders per bank (thus also the need there for the otherwise not offeirng any advatages W12)

The GT86 was largely created by axing the front half shafts on an Impreza and throwing a coupe body on it all.

Also, teh engine was pushed back significantly, those front drive shafts would now go into the front fenders or even the front door....

But yes, turning circle is alwasy an issue with FWD cars, but in this case, larger volume traverse engines cause the biggest troubles. Ask Volvo and their previous gen. of traverse inline 5s and 6s with teh turning circle of a well loaden oil tanker...